Temperature-related changes in the structure of YSAG:Yb garnet solid solutions with high Sc3+ concentration

Abstract

The paper presents the results of the Sc3+ solubility limits estimation in dodecahedral and octahedral garnet sites for 1100–1700 °C temperature range. The region of existence of solid solutions with the garnet structure in the Y2O3-Al2O3-Sc2O3 and Yb2O3-Al2O3-Sc2O3 systems narrows with increasing synthesis temperature. The Sc3+ solubility in the dodecahedral site of the YbSAG and YSAG garnets decreases with increasing temperature, and at 1700 °C it is about 64 at. %. In the octahedral site of YbSAG garnet, the Sc3+solubility decreases from 89.5 to 66.5 at. % with increasing temperature, and in the YSAG system it is about 97.5 at.%. The overall Sc3+ solubility with the simultaneous introduction into both garnet sites is lower than with doping on one of the sites and also decreases with increasing temperature. The thermal stability of the compositions belonging to single-phase regions was confirmed by vacuum sintering up to 1850 °C